Reply to: Delirium and sleep quality in the intensive care unit: the role of melatonin

To the Editor,

We read with interest the correspondence by Finsterer et al. and would like to offer a few comments.(¹) Sleep disruption and delirium in the intensive care unit (ICU) result from a complex interplay of individual, environmental, and pharmacological factors. The influence of ICU type, genetic predisposition, psychiatric history, and internal stressors is indeed relevant and contributes to this multifactorial syndrome.(²,³)

While acknowledging these numerous contributors, it is important to recognize that many are not modifiable. In addition, several interventions commonly associated with delirium, such as sedation, mechanical ventilation, and invasive monitoring, are often indispensable for the appropriate management of critical illness. In daily ICU practice, clinical focus frequently shifts toward symptom control and the implementation of feasible, low-risk strategies, particularly when high-quality evidence is limited. Within this context, sleep hygiene optimization and melatonin use may serve as adjunctive tools rather than substitutes for comprehensive delirium prevention protocols.(⁴)

Nonpharmacological interventions remain the cornerstone of delirium prevention and management in the ICU. Addressing modifiable risk factors is essential, including medication reconciliation, immobility, sleep disruption, and sensory deprivation. Furthermore, proper triage and the allocation of truly high-risk patients to intensive care while avoiding inappropriate ICU admissions are also key strategies for delirium prevention.(⁵,⁶)

Melatonin is not recommended as a direct treatment for delirium, but it may aid in restoring circadian rhythms and improving sleep quality, which could indirectly reduce the risk of delirium.(⁷,⁸) Given the limited number of pharmacologic options with proven efficacy in the ICU setting, melatonin remains a biologically plausible and safe candidate that warrants further investigation.(³,⁷)

Finally, we agree that delirium requires prompt recognition and, in selected cases, psychiatric consultation. Nonetheless, early and multimodal prevention must be a shared responsibility of the multidisciplinary team. Intensivists should be able to promptly identify, treat, and address underlying causes in critically ill patients. Therefore, systematic screening using validated tools such as Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) or Intensive Care Delirium Screening Checklist (ICDSC), ideally integrated into daily clinical assessments, is essential for timely diagnosis and management.(³)

• Publisher's note

REFERENCES

• ¹ Finsterer J, Mehri S. To: Delirium and sleep quality in the intensive care unit: the role of melatonin. Crit Care Sci. 2025;37:e20250280.
• ² Ely EW, Shintani A, Truman B, Speroff T, Gordon SM, Harrell FE Jr, et al. Delirium as a predictor of mortality in mechanically ventilated patients in the intensive care unit. JAMA. 2004;291(14):1753-62.
• ³ Devlin JW, Skrobik Y, Gélinas C, Needham DM, Slooter AJ, Pandharipande PP, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU. Crit Care Med. 2018;46(9):e825-73.
• ⁴ Soares PH, Serafim RB. Delirium and sleep quality in the intensive care unit: the role of melatonin. Crit Care Sci. 2024;36:e20240083en.
• ⁵ Slooter AJ, Otte WM, Devlin JW, Arora RC, Bleck TP, Claassen J, et al. Updated nomenclature of delirium and acute encephalopathy: statement of ten societies. Intensive Care Med. 2020;46(5):1020-2.
• ⁶ Halpern NA, Pastores SM. Critical care medicine in the United States 2000-2005: an analysis of bed numbers, occupancy rates, payer mix, and costs. Crit Care Med. 2010;38(1):65-71.
• ⁷ Bourne RS, Mills GH, Minelli C. Melatonin therapy to improve nocturnal sleep in critically ill patients: encouraging results from a small randomised controlled trial. Crit Care. 2008;12(2):R52.
• ⁸ Marra A, McGrane TJ, Henson CP, Pandharipande PP. Melatonin in Critical Care. Crit Care Clin. 2019;35(2):329-40.

Edited by

• Responsible editor:
  Jorge Ibrain Figueira Salluh https://orcid.org/0000-0002-8164-1453

Publication Dates

• Publication in this collection
  04 Aug 2025
• Date of issue
  2025

History

• Received
  19 Apr 2025
• Accepted
  24 Apr 2025